Steering mechanisms are used to steer or direct a medical instrument, for example a catheter or endoscope, to a desired position or location in a body of a patient. One known steering mechanism resembles a joystick. The configuration of the joystick usually includes a plate attached to control wires. The plate, however, must be large to accommodate the desired articulations of the steerable medical device. Additionally, the single control element encompassed in the joystick control mechanism makes the introduction of force leverage difficult, especially in a procedure during which an increased leverage is needed for different articulation planes. Further, all control wires are manipulated by the joystick, and therefore movement of the joystick may cause additional, albeit unintended, articulation of the catheter or endoscope.
Another known steering mechanism includes multiple slidable buttons. Each button is connected to a puller wire so that when the button is moved, the puller wire moves the catheter in a single direction associated with the puller wire. Thus, at least four slidable buttons are required to achieve 360 degree articulation of the catheter or endoscope. The sliding motion of the buttons on this steering mechanism makes introduction of force leverage very difficult. Furthermore, the catheter can only be articulated along one plane at a time unless the user moves more than one button at the same time, which requires that the user either use multiple fingers or continuously move his or her hand to manipulate the buttons and operate the device.